Process of refining oils.



Nrrnn STATES PAENT PROCESS OF R'EFINING OILS.

srncrrrcn'rron formingpart of Letters Patent No. 632,148, dated August29, 1899.

Application filed November 21; 1898. Serial No. 697,092. (No specimens.)

To aZZ whom it may concern.-

Be it known thatI, SIGMUND GEORGJEVITOH ROSENBLUM, a subject of the Czarof Russia, residing at London, England, have invented certain new anduseful Improvements in or Relating to the Refining and Deoolorizing ofCotton-Seed Oil and other Analogous Oils,

certain salts of iron or aluminium are the (for which application forpatent has been made in Great Britain, No. 9,824, dated April 28, 1898,)of which the following is a specification.

This invention relates to a new process by means of which certainvegetable oils can be effectively freed from the various impurities andcoloring principles, contained in them.

As is well known, cotton-seedoil asv expressed from the seed contains acertain colorlug-matter which imparts to theoil a cherryred or blackcolor and prevents its utilization for most of the industrial uses itcan be put to. At present the oil is very effectively deprived of thiscoloring-matter by a treatment with caustic alkalies, and a well-refinedoil of a pale straw color is thereby obtained. This treatment is,however, very costly on account of the great loss (up to eighteen percent. which arises from the use of alkali through the partialsaponification of the oil. It is with a View to obviate this loss and toproduce, if possible, a superior product that the process which formsthe subject of this invention has been devised.

Though the peculiar coloringmatter of crude cotton-oil has often beenthe subject of chemical research its real nature has up to the presentremained unknown. My investigation of this subject has led to thediscovery that there are two coloring principles contained in the crudecotton-seed oil, and at least one of these I was able to identify beyondany doubt and upon it to base my process of refining and decolorizingthe oil. The greater part of the coloring-matter belongs to the class ofcoloring principles known as tan-. nins and gives their characteristicblackcolor reaction with iron. After this coloringmatter, to which thered or dark-brown color of the oil is due, has been removed by suitablechemical means, as specified hereinafter, there still remains anothercoloring-matter which imparts to the oil a yellow color, and thiscoloring-matter most probably belongs to "inate and others.

the class of xanthop'hyls. Its identityhas,how-' ever, up to the presentnot been completely es tablished. As is well kn0wn, the tannins have theproperty of combining with and being'precipitated bymany metalliccompoundssuch, for instance, as those of iron, aluminium, copper,&c.-but so far I have found that most suitable for my purpose. In orderto bring about a perfect combination of the tannin coloring-matter whichis held in solution by the oil with iron or aluminium, it is obviouslynecessary to employ such compounds of these metals as would be entirelysoluble in the oil. Such compounds are, for example, all the iron oraluminium salts of the fatty acids, like ferric or aluminium oleate,stearate, palmitate, &c., also the iron or aluminium salts ofother'acids similar in nature to the fatty ones, like iron or aluminumres- Though any iron or aluminium soap may be used with the same effectin my process I for reasons of economy prefer to use the mixture of ironor aluminium i salts obtained by the double decomposition of an alkalinecotton-seed-oil soap with a suitable iron or aluminium compound. Theresulting compound practically consists of a ;mixture in varyingproportions of iron or aluminium oleate, stearate, palmitate, andlinoleate; but if soaps from other oils be used the resulting compoundwill vary in proportions and composition. 7 the compound iron oleatealone is added to When, for example,

crude cotton-seed oil, the iron compound com- I bines with the tannincoloring-matter, and a deep brownish-black color is imparted to the oil.On examining a thin layer of the sotreated oil on a transparent surfaceit will be found that the oil which before addition was I perfectlyuniform in appearance now contains a very finely-divided blackprecipitate,

which imparts to it the dark color, while the oil itself is of alight-yellow color. This precipitate is, however, so finely divided thatas far as I am able to ascertain it cannot be separated from the oil byfiltering media of the closest texture. In order to separate the nowlight-colored oil, it is necessary to bring this very finely dividedprecipitate into such a form as to enable it to be retained by filteringmedia which are in ordinary technical use.

This object can be attained by a very great variety of means; but forthe purposes of my invention I have so far found it most suitable toproceed as follows: I add to the oil treated as above asmallamount ofstrong ammonia (aminonium hydrate) and incorporate it by suitablernechanical means very intimately with theoil.Theeffectoftheammoniaistoprecipitate the ferric tannate (mixed withferric hydroxid) in the form of a black flocculent precipitate, which isthen easily removed from the now light-colored oil bya simplefiltration. As alluded to above, a great variety of compounds will havea similar or the same effect upon the ferric tannate as ammonia. Suchcompounds are, for example, alkaline carbonates, hydroxids, phosphates,ammoniagas, and many others; but so far I have found that ammoniumhydrate is most suited for my purpose.

Having given an outline of the main reactions upon which my process isbased, I will now shortly describe how I propose to carry it out inpractice. I dissolve in the crude cotton-seed oil at a moderatetemperature a small amount of the fatty ferric compoundsay ferricoleate-(O.1 to 0.2 per cent. of the weight of the oil has been found tobe quite sufficient,) and I then leave the oil to stand for some time ata moderately warm temperaturesay about 130 to 150 Fahrenheitmixing itfrom time to time in order to bring about a complete combination of thetannin coloring-matter with the iron. I then pour into the oil asuitable amount of ammonium hydrate (one percent. of the weight of theoil has been found to be sufficient) and emulsify the mixture by anysuitable mechanical means. The mixture at first assumes a rather thickconsistency, but after the emulsifying has proceeded for a short timethe mixture reverts to the normal consistency of the oil, and this stageof the process is then completed. The oil is then passed through anysuitable filtering material which is capable of retaining the blackprecipitate, and an oil of a golden-yellow color is thus obtained. Thewater of the ammonium hydrate is entirely absorbed by the blackprecipitate, and thus the oil after having been separated from theprecipitate is clear and practically free from water. The oil, however,contains a trace of gaseous ammonia which imparts to it a slight thoughcharacteristic smell of ammonia. This smell is easily removed from theoil by passing a rapid current of air through the oil for a few minutesor by heating it for a very short time at a moderate temperature. Boththese methods will also remove any traces of water which may be still inthe oil, and thus dry it effectively. The oil is now of a golden color.This yellow color is, as far as I have been able to ascertain, due toanother coloring principle belonging to the class of xanthophyls and canbe easily removed from the oil by heating it briskly to a temperature ofabout 150 Fahrenheit. This done, the oil will be of a very pale strawcolor.

Oil treated by the above process is not only freed from the coloringmatters contained therein, but also from the so-called mucilage, whichis carried down by the black pre cipitate during the process andfiltered out together with it. In fact, as ascertained by chemicalanalysis oil treated by my process is of a much higher degree ofrefinement than the best refined cotton-seed oils at present on themarket. The process if carried out properly does not involve anyappreciable loss of oil and does not introduce any impurities whichcould be prejudicial to the use of the oil.

Oil prepared by this process is absolutely free from iron. The amount offree fatty acids which of necessity is introduced into the oil by theuse and subsequent decomposition of the fatty iron salt or salts is toosmall to be of any practical disadvantage.

In the above process although iron oleate was added alone to thecotton-seed oil equally good results are obtained by the use of anyiron, aluminium, or other similar metallic soap.

I claim- 1. The process of refining cotton-seed and other analogous oilsby treating the crude oil with a metallic soap, consolidating theprecipitate thus formed by adding an alkali, separating the precipitateand subsequently heating the oil to remove the yellow coloringmatter.

2. The process of refining cotton-seed and other analogous oils bytreating the crude oil with a metallic soap and consolidating theprecipitate thus formed by adding an alkali-- such as ammonia.

In testimony whereof I have hereunto set my hand in the presence of thetwo subscribing witnesses.

SIGMUN D GEORGJEVITCH ROSENBLUM.

\Vitnesses:

SELMA WENSTENFELD, \VILMER M. HARRIS.

